debris separator capable of 5,000 gpm

[sef]

Many nuclear plants have a problem in a particular mode of operation. During some postulated accidents, the reactor containment building is expected to be very deep in water. At a certain point, this water becomes a pseudo-tank from which pumps take suction. As you can imagine, the reactor containment building is not a nice clean tank. We expect dirt and pieces of insulation to migrate to the sump from which the pumps take suction. All plants have a screen built over and around that sump. Many studies postulate that this screen becomes clogged with said debris. I was wondering about getting rid of the screen and processing the water through a separator to allow the laws of physics to shoot the debris into the bottom of a tank-like component and take suction from the top of the same tank. Do you know of such a system that could handle 1000s of gallons of water per minute? [/red] How do I get rid of the debris that would fall in the bottom of the tank? I've also seen suction strainers with an active system to blast the debris off of the screen -- spraying from the "inside" (re Yardney company product). Although that seems to fit the bill, it still leaves the question of what to do with the debris piling up around the sump.

 

[dicksewerrat]

What kind of heads are you looking at? Look at axial flow pumps for low head, high volume.

 

[sef]

Thanx for looking in at this one. Unfortunately, the pumps served by the above described sump have hundreds of regulations and license conditions associated with them, and are thus just about impossible to change out. Nevertheless, the head of water on the suction side of the pumps is roughly 20 feet when the containment is fully flooded and expected to go into the recirculation mode of operation.

The sump actually serves five pumps -- 3 high head (~1400 psig), and 2 lower head pumps (~300 psig). The 3 HPSI pumps are charged with restoring inventory in the reactor coolant system following a relatively small break in pipe between the reactor vessel and steam generators. The other two pumps, containment spray pumps, send water into ring headers in the ceiling of a ~1E6 CuFt building enclosing the reactor coolant system. Containment spray quenches steam coming from the break in the primary system.

 

[dicksewerrat]

Try 'Stormceptor' they make a structure that filters stormwater flows. They may be able to help.

 

[oxilume]

Sef,

Can you provide a debris size distribution(D50). Will solids/liquids separator be located within the Reactor Room? Will the separator be used on primarly loop or secondary loop water?

Respectfully,
Todd Foret
toddforet@usa.net

 

[sef]

Todd Foret:

Thanx for replying. The separator will be in the containment building. The plant design includes a feature that collects water spilled from a break in the reactor coolant system (primary loop) in a sump. That water becomes the source for the emergency core cooling pumps in the recovery phase of the postulated event.

The problem is that when the reactor coolant system breaks, the water comes out at high temperature (~550 DEGF) and starting around 2200 psi. That kind of water tends to rip insulation etc. on the primary loop near the break to shreds. Large and small pieces of insulation migrate to the sump mentioned above. The current screen on the recirculation inlet is just that -- a heavy duty screen. The screen is now postulated to clog with the debris created by the break in the reactor coolant system.

During the recirculation phase, the water can be under up to 60 psi of pressure and maybe close to saturation temperature.

I'd appreciate any good suggestions on an effective sump screen.

Steven Farkas